Chances are they don’t have parts for older models. That’s what “Just in time” manufacturing is about, and Apple is fairly good at that. Also, if they had them

Chances are they don’t have parts for older models. That’s what “Just in time” manufacturing is about, and Apple is fairly good at that. Also, if they had them, chances are you would find the parts too expensive. They would either have to keep a production line running for low quantities of products, build a new one specialized for small production runs, or stock parts for years. Both have significant costs. For example, let’s suppose they decide to stock parts, and plan perfectly, so that all parts can be sold over a period of 10 years. On average, that’s five years between spending money on producing the part and getting money back on selling it. That likely warrants at least a 25% price increase. Unfortunately, I don’t think there’s a business for offering electronic parts in the long-term (old timer cars are a different case, as many parts can be made almost by hand, and customers are willing to pay good money for them)